Method of recovering sulfate crystals.



No. 863,279.: PATENTE AUG. 13, 139'07. H. E.' Hamon an. P.' c. 659GB; .METHOD of covxms' 'SULPATE cRYsTALs.

.LPPLIDATIOI FILED HAY 11, 1906.

3 BEEETS-BHEET l.

WITNESSES 7. o 9 1 3.. l G. U A D E T N E. AH PD E G Fw U... N 0 T R 0 H L nm 0m 7 2, 3 6 8 o. N

METHOD 0F REGOVBRING SULFATE CRYSTALS.

APPLICATION FILED HAY 11, 1908..

3 SHEETS-SHEET 2.

WITNISBIS No. 863,279. PATENTED AUG.13, 1907.

` H.'B. HORTON L F. C. GEDGE. METHOD 0F RECOVERING SULFATE CRYSTALS.

APPLICATION FILED MAY 11. 1906.

3 SHEETS-SHEET 3 wsTNf-:SSES

UNIT-En STAI-IESv PATENE ACIEEICE.

HORACE E. HCRTCN, or WAUKEGAN, AND FREDERICK C. CEDGE, 0E EvANsToN, ILLINOIS,V AssIGNoRs -To AMERICAN STEEL a WIRE COMPANY, CE WORCESTER',-MASSACHUSETTS,

A CORPORATION. OF NEW JERSEY.'

speci/Canon Letters Patent.

SULEATE CRYSTALS.

Patented Aug-13, 1907,

, Apjiimiuredmy11.1906, SeriaiNo. 316,297.

To all 'whom-fit may concern! Be it-known .that we, HQRACE E. HoRToN, of Waukegan, county of Lake, State of lllinois, and'FREDf 3 ERICE C. GEDGE, of Evanston, countyof Cook,\State of Illinois,` have invented a new and useful Method ofA Recovering Sulfate Crystals, of which the following is a specification, reference being had to the accompany-- ing drawing, in Which- Figure is a plan view of apparatus suitable for the practice of our invention; Fig. 2 is a vertical sectional view on the line 2, 2 of Fig. 1; Fig. 3 is a vertical seetion'on a largerV scale, showing the crystallizing tank;

Fig. A4 is a plan view of Fig. 3, and Fig. 5"is a sectiona l. i view showing the meansvwhich We employ for separat.

ing lthe water from the crystals.

The purpose of' our invention is to for recovering sulfateof iron from the liquor which results from the, pickling of *iron wire, rods, etc. in an acidbath. f

Our invention provides means by -which a valuable commercial product canbe obtained'in this way, and also provides 4for obtaining the product theforxn of small crystals or granules of substantially uniform size and substantially uniform purity andl much drier than' the `larger crystals heretofbre obtained Asc that the processis availablefor crystals to be usedin the arts for'the purification of water and for other purposes for which such sulfate is employed. i

The invention is also applicable,l with suitable changes in the materials 'of whichthe apparatus made, to -the recovery of sulfate of copper from the liquor resulting'fr'om the pickling of copper Wire, rods, etc. Y In the practice of our invention, We take the sulfuric acid liquor from the pickling vats and deliverit to suitable storage tanks 2 in Which'it is neutralized steel scrap. These tanks are preferably provided vWith vsteam-coils to heat the solution somewhat in order'to prevent premature crystallizing in the tanks. When the solution becomes neutralized, that is to say, When the free acid hasbeen substantially satisfied by the iron with which` it comes in Contact, the solution is removed by pumps into a settling-tank 3 in which the` vmechanical impurities are settled by gravity,i. and fromithis settling-.tank the solution is drawn successively into vacuum evaporators 4, 4, 4, known in the art as multiple effects. A suitable number of these effects may be employed. Each one con`^ Vtains tubes preferably made of copper, and the effects are providedwith vacuum-producing apparatus.

'l`he dilute neutralized liquor is supplied to the first ffect, where it comes into contact with and circulates provide means around the copper tubes, which are filled with a heat- `ing medium, and in this effect a partof the water-passes off-in the frniof vapor.vr The liquor then passes to the second effect, in which it is further evaporated, and in the saine manner to the 4other effect or effects, where it is finally concentrated. rlfhe steam supplied to the coils fof the firsteffect may be exhaust steam or live .steam from an outside source, and the steam for the fleeting-coils of ther second leffect 'may be obtained by utilizing the vap'or generated by the boiling of the liquor in the rst effect. "Int'the same `mannerthe vapor from the second leffectimay bepassed to Vthe coils Vof thethird effect, and so on, the vapors from the liquor .in the'nal effect being, passed into a suitable condenser equipped with avacuurn' pump.

livered by a pump 5 to the Crystallizing-tanks 6, 6. As Vshown in Figs. 2, 3 and 4, these crystallizing-tanks are. provided with coils of pipe 7 through which cold' water tanks 11. The seare preferably constructed as shown in Fig'. '5, each tankhaving at the bottom a screen 12,

, `beneath which'is a space 13 communicating by a pipe 14' with a vacuhm pump and having a liquor-discharging ontlet 15. Ther-.suction produced by the vacuum pump'aids in removing the liquor from the crystals in 7the tank 11. 'The mother liquor passesoutthrough an outlet 15. and the crystals remain on the screen l2.

These crystals are then removed, preferably by shoveling, into a drier," preferably a r'tary drier, 16, in which the crystals are thoroughly and evenly dried. From thence the crystals are discharged to a conveyer 17 by which thymay be removed to storage bins or disposed of in-any convenient Way.

. The process above described is lsimple and` extremely -efficient The crystals which are produced are of con.

are of great valeinlthe arts. V

tion in the crystallizing-tanks is preferably about fifty degrees Fahrenheit, but this may be varied as desired. Roughly speaking, the amount of salt which is deposited from the solution in the crystallizirig-tanks will be venient size; they contain a minimurp of moisture, and

' From the nal effect, the concentrated liquor is def or brineis caused to circulate so as to cool the liquor The temperature to which. we prefer to bring the solu- I governed by the temperature of the solution, as the solubility of the salt in water varies at different temperatures. Instead of bringing the nuetralized liquor into contact with a metal, We may employ any suitable' metallic hydrate, oxid or carbonate in any suitable manner.

Within the scope of our invention' as stated in the claims, changes may 'be made in the apparatus and in the steps of the process. Some ofthe steps of' theprocess may be employed Without others1 or may be employed in other combinations7 since What we claim is: t 1. A -procossl ot obtaining in a continueus lnanner.- a metallic sulfate in the forni of small crystals, which convsis'ts in at least partially neutralizing.; an acid solution nl a metallic sulfate by adding the samemetal as the base ofthe sulfate, transt'erling,"v the solution t0 a separate vessel where the impurities separate, then withdrawing;l and crap oratlng the solution in a vacuum, to the crystallizing point.

then transferring; it to a crystallizing tank and 'simultane` ously agitating and artificially cooling the solution in suc xcessive tanks substantially as described.'

'2. A process of obtaining in` a continuous, manner a *crystalline metallic sulfate, which consists ln at least ,parA

'25 tially neutralizing an acid solution of a metallic sulfate by adding the 'samemetal as the base ot the sulfate, maintaining such solution at a temperature :there the crystal li`zing point, then cvaporating the solution in a vacuum to the crystallizing point, and then' transferring it to a crystallizinp; tank and simultancousely agitating and artificially cooling the solution in the tank to produce crystals of sinnll granular forni; substantially as described.

li. A process o1' obtaining' in a continuous manner a crystalline metallic sulfate, which consists in atleast partially ueutralizingian acid solution of a metallic sulfate hyadding the' saine metal as the base of thejsulfate, continuously withdrawing the treated solution and concentrating' it to the crystallizing point in successive steps under vacuum while maintaining a substantially constant `crystallizingr tanks in a substantially continuous manner,

and simultaneously artificially cooling and agitating the v' hot solution successively in the. successive crystallizing tanks to which it is fed L substantially as described.

lu testimony whereof, we' have hereunto set our hands.

, Hoi-ACE n.'"HOR'r0N.

'FREDERICK c. (innen.

Witnesses:

A. T. WEAVER, yA. F. ALLEX. 

